Campbell & Turner 2018, Debunking exercise-induced immune suppression

Argues that the “open-window” immunosuppression reading is largely an artefact: the post-exercise fall in blood lymphocytes reflects redistribution of cells to peripheral tissues (heightened surveillance), not suppression, and reliable evidence that vigorous exercise raises opportunistic-infection risk is limited. A widely cited mechanistic reframing, though a narrative review rather than new trial data. Moderate to strong.